Этот файл используется другим процессом

 Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Shown
        If File.Exists("lon") = False Then
            File.Create("lon")
        End If
 
 End Sub

Dim str As New StreamWriter("lon")
str.WriteLine(name2)

Application.StartupPath & "\File.noext"

Imports System.IO
 
Public Class Form1
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Shown
        If File.Exists("lon") <> True Then File.Create("lon")
    End Sub
    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Dim sw As New StreamWriter("lon", True, System.Text.Encoding.GetEncoding(1251))
        sw.Write("name2")
        sw.Close()
    End Sub
End Class